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Article
Concomitant Clustering and Ordering Leading to B2 + BCC Microstructures in Refractory High Entropy Alloys
The presence of substantial concentrations of multiple principal elements in high entropy alloys or complex concentrated alloys, inevitably results in competing for clustering (or phase separation) and orderin...
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Article
Open AccessGeneralization of intrinsic ductile-to-brittle criteria by Pugh and Pettifor for materials with a cubic crystal structure
Two classical criteria, by Pugh and Pettifor, have been widely used by metallurgists to predict whether a material will be brittle or ductile. A phenomenological correlation by Pugh between metal brittleness a...
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Article
Open AccessHigh entropy alloys as a bold step forward in alloy development
Diluting a base element with small amounts of another has served as the basis for develo** alloys for thousands of years since the advent of bronze. Today, a fundamentally new idea where alloys have no singl...
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Article
Open AccessMicrostructural Design for Improving Ductility of An Initially Brittle Refractory High Entropy Alloy
Typically, refractory high-entropy alloys (RHEAs), comprising a two-phase ordered B2 + BCC microstructure, exhibit extraordinarily high yield strengths, but poor ductility at room temperature, limiting their e...
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Article
Open AccessA predictive structural model for bulk metallic glasses
Great progress has been made in understanding the atomic structure of metallic glasses, but there is still no clear connection between atomic structure and glass-forming ability. Here we give new insights into...
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Article
Open AccessAccelerated exploration of multi-principal element alloys with solid solution phases
Recent multi-principal element, high entropy alloy (HEA) development strategies vastly expand the number of candidate alloy systems, but also pose a new challenge—how to rapidly screen thousands of candidate a...
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Article
Microstructure and Properties of Aluminum-Containing Refractory High-Entropy Alloys
A new metallurgical strategy, high-entropy alloying (HEA), was used to explore new composition and phase spaces in the development of new refractory alloys with reduced densities and improved properties. Combi...
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Article
Oxidation behavior of a refractory NbCrMo0.5Ta0.5TiZr alloy
Isothermal oxidation behavior of a refractory high-entropy NbCrMo0.5Ta0.5TiZr alloy was studied during heating at 1273 K for 100 h in flowing air. Continuous weight gain occurred during oxidation, and the time de...
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Article
Microstructure and elevated temperature properties of a refractory TaNbHfZrTi alloy
Compression properties of a refractory multi-component alloy, Ta20Nb20Hf20Zr20Ti20, were determined in the temperature range of 296–1473 K and strain rate range of 10−1–10−5 s−1. The properties were correlated wi...
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Article
Slip System Modification in NiAl
An effort to modify the slip vector in the B2 compound NiAl was undertaken to overcome the brittle failure associated with the <100> slip vector which typically operates in this compound. Alloying additions we...
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Article
Microstructure engineering of titanium alloys via small boron additions
Several studies, dating back to 1950s, were conducted on the addition of boron to titanium alloys, with an aim to improve the stiffness and strength. The majority of these efforts did not lead to successful tr...
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Article
Fatigue and Fracture Behavior of a Ca-Based Bulk-Metallic Glass
The compression and fatigue behavior of a Ca65Mg15Zn20 bulk-metallic glass (BMG) was studied in air at room temperature. During the preparation of cubical samples of the Ca65Mg15Zn20 for compression and fatigue i...
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Chapter and Conference Paper
Solidification Microstructure and Texture in Grain-Refined Titanium Alloys
In the present study, solidification microstructure and texture evolution in grain-refined Ti-6Al-4V and γ-TiAl alloys via trace boron addition are compared with their baseline counterparts. Boron addition res...
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Article
Effect of Al Addition on Glass Forming Ability and Glass Stability of Ca-Mg-Zn-Cu Based Bulk Metallic Glasses
The effect of Al addition on glass forming ability (GFA) and stability of the glassy phase against crystallization was studied for Ca-Mg-Zn, Ca-Mg-Cu, and Ca-Mg-Zn-Cu alloys. The glassy alloys were produced by...
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Article
Open AccessDevelopment and Characterization of Low-Density Ca-Based Bulk Metallic Glasses: An Overview
Ca-based bulk metallic glasses (BMGs) have unique properties and represent a new seventh group of BMGs. Many of them have excellent GFA, which can be related to their efficient atomic packing, low onset drivin...
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Article
The microstructural characterization and simulation of titanium alloys modified with boron
Strength and stiffness of conventional titanium alloys (e.g., Ti-6Al-4V) can be significantly improved while maintaining adequate fracture properties via additions of small amounts of boron. Boron-modified tit...
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Article
Cryogenic and elevated temperature strengths of an Al−Zn−Mg−Cu alloy modified with Sc and Zr
The effect of minor additions of Sc and Zr on tensile properties of two developmental Al−Zn−Mg−Cu alloys was studied in the temperature range −196°C to 300°C. Due to the presence of Sc and Zr in a fine dispers...
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Article
Electrochemical behavior of Ca-based bulk metallic glasses
Since 2002, numerous Ca-based bulk metallic glass (BMG) alloys have been discovered. These BMG alloys are of interest because of their low densities and costs; however, few studies have examined the properties...
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Article
Powder metallurgy Ti-6Al-4V-xB alloys: Processing, microstructure, and properties
This article describes processing of Ti-6Al-4V-xB alloys via pre-alloyed and blended elemental powder metallurgy techniques. The influence of processing on the microstructural evolution and mechanical properti...
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Article
A Thermodynamic Model for Amorphization and Topological Criteria
A thermodynamic model for amorphization is developed which allows analysis of the effect of composition, atomic radii, and elastic constants of constitutive elements on amorphization. The model is based on com...
